Rockable outer-jaw pipe wrench having slidable inner jaw actuated by rotatable handle



J. A. MITCHELL ROGKABLE OUTER-JAW PIPE WRENCH HAVING SLIDABLE INNER-JAWACTUATED BY ROTATABLE HANDLE 2 Sheets-Sheet 1 T NM Filed Dec, 30, 1947INVENTOR. I JZ/We'w flJZ/fC/Ze Nov. 1, 194% J. A. MiTCHELL ROCKABLEOUTER-JAW PIPE WRENCH HAVING SLIDABLE INNER-JAW ACTUATED BY ROTA'IABLEHANDLE Filed Dec. 50, 1947 2 Sheets-Sheet 2 Patented Nov. 1, 1949 UNITED RCKAIBLEOU'IER-J AW BIPEWVRTEN'CH HAV- ING SLIDABIiE I INNER LIA-WAGTUATEDBY -;'ROTATABLE eHANDLE James A.IMitchell,' LittleRo'ck, Ark.

. Application December 30, 1947-;iSe1-ial No. 794,641

.2 Claims. 1

'lhiszinvention relates to improvements in pipe wrenches andmoreparticul-arly to a quick-adjustable. pipe wrench for holding orturning i cylindricalzbodies of various sizes.

.wltsisrramong theobjectsof the invention to provide an ..impro.ved pipeWrench which is quickly; adjustable. to grip cylindrical bodies ofvarious :sizes; is :locked in adjusted condition against .iaccidentalslippage, automatically tightens-upon; a;:cylindrica1 body disposedbetween thew-jaws thereof when subjected to body turning pressure isquickly-and-easily freed-from its=turningengagement.with a cylindricalbody by .-a.- short backwardmovement of the handle which-.forces thejaws .of the wrench apart and eliminates-sticking, is .strong anddurable in construction, and is economical to manufacture.

.Other objects .and advantages will become apparentlfroma consideration,of the following .description inconjunction with the accompanying.drawings, wherein:

Figure 1 is a longitudinal elevation of apipe wrench illustrative-of theinvention.

.Figure 2 isatop plan view of the wrench i1- lustrated in Figure 1.

Figure 3 is a transverse cross-section onan enlarged scale takensubstantiallyv on the line 3-1-3 .of Figure 1.

.Figure' 4..is afside elevation on an enlarged scaleof a fragmentaryportion of the wrench showing the partsin a different operativepositionifrom thatillustrated in Figure 1. and havingvportionsbrokenaway and shown in crosssections to better illustrate .the constructionthereof.

Figure is a view similar to.'Figure 4 showing the parts of the wrench ina still difierent operative" position and with additional parts brokenawayand-shownin cross-section.

Figuret is a view similar to Figures4 and 5 but showing the parts 'ofthe'wrench'in a differentposition from that shown in Figures 4 and *5.

Figure 7 is an end elevation of a bracket'cons'tituti-n'g'*an'operativecomponent of the wrench.

*With continued reference to the drawings, the improved pipe wrenchcomprises in general, a screw shaft-l0 having a tubularycylindrical;coaxialhandle- -l l on one end thereof; a bracket l2' -journa-led on theend ofthe screw shaft opposite thehandle, an outer jaw member 13pivotally *connected to the bracket and an inner jaw member l4 slidablysupported by the bracket and pivotally and'slidably connected to theouter jaw "member '13.

z FI 1 1e-,'screw ishaft1 110 is" provided at-the5 end thereof oppositethe handle l I with. a cylindrical, c-oaxialarbor "i5 of reduced.diameter and-a screwethreaded section I Eds secured on this. arborbetween 1: the--ends thereof and drivingly .6011- nected with.thearborby. suitable means :such

assthe. keys? and. keyways cl 1;. and 18 @particularly illustratedzinFigure 3.

aBracket member 42 is. a generally rectangular 'bodyihaving a pair-ofspaced-apart, apertured substantiallyparallel legs .19 and 20in whichthe arbor -l5--isjournaled theeleglfl being disposed between ,thescrew-threaded section .1 6 :and .the adjacent .end ofthe.threadedvportion .of the screwrshafmhas is: clearlyil-lustrated inFigure 5. This bracket furtherhasa .cur-Ved top portion 2|. candle..bottom .portion, 22,. the .two l'egs and the top and bottomportionbeingspacedapart to provide. va substantially square aperture in:the bracket which receives the screw-threadedisection-JB. Theouter .endof the arbor l5ispreferably. beaded vover. as indicated vat-23-to securethe-arbor inlthe bracket. Thetop portion 2| of the'bracket. isprovided.at the. end thereof opposite Lthe. screw. .shaftwith an apertured lug24 extendinglbeyondthe endof-the arbor i5 and receiving a transverse..pin 25 .the ends of which provides opposite shoulders.disposedone: ateach side of the .lug and .the bottom portion 22 of the [bracket isprovided with .a longitudinal guideway 26 substantially parallel to theaxisv of screw shaft ill, and with an inclined camnotch 27 whichisdirected toward .the handle-end of the screw shaft at an angle of.approximately .45 degrees tothe screw shaft axis.

Theo'utenjaw member l3. has a straight shank 28 ofrectangulancross-section from. one end of which the outer .jaw 29extends substantially perpendicular .tothe shank. Theinner face of thisouter jawif29 is.serrated -or toothed, as indicated at '30, to securely.grip a cylindrical body to which the wrenchsis applied. At its endopposite the jaw"29"the shank '28.,is extended into a pair Theseabutments 33 are located at the side of pin 25 adjacent the handle endof screw shaft I0 and bear against the respective ends of the pin undercertain operating conditions of the wrench, as will be later explained.

The inner jaw member I4 has an elongated rack bar 34 slidably receivedin the guideway 26 of the bracket and held by this guideway constantlyin mesh with the threads of the screw shaft in. It is here pointed outthat the screw shaft threads have a very steep pitch, approximating anangle of 45 degrees, so that the rack bar 34 is rapidly advanced andretracted upon rotation of the screw shaft. An inner jaw 35 is providedat the end of rack bar 34 adjacent the outer jaw 29 and a pair ofspaced-apart apertured cars 35 extend from this jaw past the shank 28 ofthe outer jaw, straddling the shank, and a pin 3'! is secured at itsends in these apertured ears at the side of shank 28 opposite the innerjaw 25 to pivotally and slidably connect the inner jaw member to theshank of the outer jaw member. The surface of the end of the inner jawmember adjacent the shank is curved to provide a cam surface 38 and theinner face of the inner jaw 35 is provided with serrations or teeth 39to I firmly grip an object, such as the cylindrical body 40 shownbetween the wrench jaws in Figure 1.

The leg 20 of bracket [2 is provided with a pair of tapered stops 4|disposed one at each side of the bracket leg and engageable incorresponding notches 42 provided in the plates 3| respectively at thislocation and the end of the rack bar 34 opposite inner jaw 35 isslidably secured to the screw shaft by a metal loop 43 surrounding thescrew shaft and secured at its ends to the corresponding end of the rackbar by suitable means, such as the pegs or rivets 14.

The operation of the wrench is substantially as follows:

In applying'the wrench to a cylindrical object such as a pipe section40, the outer jaw 29 is hooked over the object and the handle I l isthen rotated to turn screw shaft II) to advance the rack bar 34 untilthe inner face of the inner jaw 35 is also brought into contact with theobject. The outer and inner jaws 29 and 35 then bear against theopposite sides of the cylindrical object with a suificient amount ofpressure to set the wrench or cause it to firmly grip the object whenforce is applied to handle H to rotate the object. Before theapplication of object rotating force to the handle H, the stops (H arespaced from the bottom of the corresponding notches 32, as illustratedin Fig. 4. Pin 32 is also spaced from the inner end of notch 21. Whenthe handle is moved clockwise, asviewed in Figure 1, the inner jawpivots relative to the shank of the other jaw upon the cam surface 38,carrying with it the screw shaft It and bracket l2, and abutments 33 arebrought into contact with the corresponding ends of pin 25. With the pin25 in operative contact with the abutments 33, a leverage is exertedbetween the location of this contact and the location of the contact ofthe threads of the screw shaft with the teeth of the rack bar whichleverage tends to pull the outer jaw inwardly toward the inner jaw toprovide a gripping action of the wrench. This movement is limited bycontact of tapered stops 4| with the bottoms of notches 62 so that theforce will not be sufilcient to crush an object such as a cylindricalpipe joint. When the turning force is released and the wrench backed upfor another bite, pin 32 moves outwardly innotch 21 thereby separatingthe inner and outer jaws and freeing them on the pipe.

The wrench is easy to adjust, may be operated very quickly and firmlygrips a cylindrical object, such as a pipe joint when pipe-turning forceis applied to the handle thereof. It is also extremely rugged inconstruction and is not easily damaged in use.

The invention may be embodied in other specific forms without departingfrom the essential characteristics thereof. The present embodiment istherefore to be considered in all respects as illustrative and notrestrictive, and the scope of the invention being indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

What is claimed is:

1. A pipe wrench comprising a screw shaft having a coaxial tubularhandle at one end and a pair of spaced-apart arbor portions adjacent theopposite end thereof; a rectangular bracket having spaced-apart legsjournaled on said arbor portions, a lug extending beyond the adjacentend of said screw shaft, a guideway extending therethrough parallel tosaid screw shaft, a machined cam notch therein at the side of saidguideway remote from said screw shaft, and a pair of tapered stopsdisposed one at each side of said guideway; an outer jaw member having astraight shank, a jaw extending from one end of said shank substantiallyperpendicular thereto, a pair of substantially-parallel, spaced-apartplates extending from the end of said shank opposite said jaw andstraddling said bracket, said plates having apertures therein at thelocation of the cam notch in said bracket, and a pair of inclinedabutments disposed one at the inner side of each of said plates at thelocation of said lug; oppositely disposed shoulders on said lugrespectively engageable with said abutments; a pin extending throughsaid cam notch and secured at its ends in said plate apertures; and aninner jaw member having a rack bar slidable in said bracket guideway andheld in mesh with said screw shaft; a jaw on one end of said rack barsubstantially perpendicular thereto, a pair of apertured ears on saidjaw straddling said shank; and a pin secured at its ends in said earsand disposed at the side of said shank opposite said inner jaw, wherebysaid inner jaw is adjustably movable relative to said outer jaw byrotation of said screw shaft and said jaws are relatively moved to Jprovide a gripping action by pressure of said abutments against said lugshoulders.

2. A pipe wrench comprising an exteriorly threaded screw shaft having acoaxial, cylindrical handle on one end, a bracket journaled on saidscrew shaft'at the opposite end thereof and having a guideway in spacedrelation beneath and substantially parallel to the axis of said screwshaft, an outer jaw member including a shank, an outer jaw on the distalend of said shank, and a pair of spaced-apart plates on the proximal endof said shank rockably straddling said bracket, a lug and an inclinedabutment connection between each of said plates and said bracketdisposed on each side of said screw axis, and an inner jaw memberincluding a rack bar positioned below the axis of said screw shaft andslidable in said bracket guideway, said rack bar having teeth on itsupper side meshing with the threads of said screw shaft, an inner jaw onthe end of said rack bar adjacent said outer jaw, and a loop on saidinner jaw slidably and pivotally embracing the outer jaw and limitingrocking movement be- The following references are of record in the fileof this patent:

6 I UNITED STATES PATENTS tween the inner and outer jaws Number NameDate 392500 Armstrong et a1. Nov. 6, 1888 JAMES MITCHELL 5 566,299Downey Aug. 25, 1896 1,637,590 Robinson Aug. 2, 1927 REFERENCES CITED1,774, 23 Anderson Aug. 26. 1930

